Oilpan: have ResourceFetcher use a prefinalizer.

Source/core/fetch/ResourceFetcher.h

Index: Source/core/fetch/ResourceFetcher.h
diff --git a/Source/core/fetch/ResourceFetcher.h b/Source/core/fetch/ResourceFetcher.h
index 1c6135f739c9a5b108d8179c41921bbc6edbf113..1bdf8d52924f4d901ddb1004869823297ae2aada 100644
--- a/Source/core/fetch/ResourceFetcher.h
+++ b/Source/core/fetch/ResourceFetcher.h
@@ -68,6 +68,7 @@ class ResourceLoaderSet;
 // alive past detach if scripts still reference the Document.
 class CORE_EXPORT ResourceFetcher : public GarbageCollectedFinalized<ResourceFetcher> {
     WTF_MAKE_NONCOPYABLE(ResourceFetcher);
+    WILL_BE_USING_PRE_FINALIZER(ResourceFetcher, clearPreloads);
 public:
     static ResourceFetcher* create(FetchContext* context) { return new ResourceFetcher(context); }
     virtual ~ResourceFetcher();